Fast wide-field Raman spectroscopic imaging based on multi-channel narrow-band imaging and Wiener estimation

The speed of data acquisition is a major hurdle for hyperspectral spontaneous Raman imaging to be widely adopted in the clinical setting. To address this problem, we proposed a new approach to achieve fast spectroscopic imaging while keeping high spectral resolution, in which narrow-band or wide-band imaging quickly captures all required data and then full spectra at all pixels are reconstructed efficiently. We started by developing a method to enable the reconstruction of diffuse reflectance spectra from color images with high accuracy. This method was further developed for hyperspectral Raman imaging from narrow-band measurements. Then a series of Wiener estimation based methods were developed to improve the accuracy of spectral reconstruction and reduce the need of acquiring a training dataset. A four-channel Raman imaging system has been built to acquire all narrow-band images in one single frame and an eight-channel imaging system is currently under evaluation. This technique could speed up the acquisition of hyperspectral data cube by two to three orders of magnitude, which opens the possibility of rapid Raman imaging for the monitoring of dynamically changing events in biological samples. Moreover, other hyperspectral imaging modalities including diffuse reflectance and fluorescence imaging can also benefit from this fast spectroscopic imaging technique, which have been demonstrated in flap assessment during plastic surgery on an animal model.